+ Athira Rajeev
On 3/2/2021 8:31 AM, Thomas Richter wrote:
Executing perf test 27 fails on s390:
[root@t35lp46 perf]# ./perf test -Fv 27
27: Sample parsing
--- start ---
---- end ----
Sample parsing: FAILED!
[root@t35lp46 perf]#
The root cause is
commit c7444297fd3769 ("perf test: Support PERF_SAMPLE_WEIGHT_STRUCT")
This commit introduced a test case for PERF_SAMPLE_WEIGHT_STRUCT
but does not adjust non-x86 weak linkage functions.
The error is in test__sample_parsing() --> do_test()
Function do_test() defines two structures of type struct perf_sample named
sample and sample_out. The first sets member sample.ins_lat = 117
Structure sample_out is constructed dynamically using functions
perf_event__synthesize_sample() and evsel__parse_sample().
Both functions have an x86 specific function version which sets member
ins_lat. The weak common functions do not set member ins_lat.
I don't think Power supports the instruction latency. As a request from
Athira Rajeev, I moved the PERF_SAMPLE_WEIGHT_STRUCT to the X86 specific
codes.
https://lore.kernel.org/lkml/[email protected]/
https://lore.kernel.org/lkml/[email protected]/
I don't think we want to add the ins_lat back in the weak common functions.
Could you please update the perf test and don't apply the
PERF_SAMPLE_WEIGHT_STRUCT for the non-X86 platform?
Later in function samples_same() both data in variable sample and sample_out
are compared. The comparison fails because sample.ins_lat is 117
and samples_out.ins_lat is 0, the weak functions never set member ins_lat.
Output after:
[root@t35lp46 perf]# ./perf test -Fv 27
27: Sample parsing
--- start ---
---- end ----
Sample parsing: Ok
[root@t35lp46 perf]#
Fixes:
commit c7444297fd3769 ("perf test: Support PERF_SAMPLE_WEIGHT_STRUCT")
I think the regression should start from
commit fbefe9c2f87f ("perf tools: Support arch specific
PERF_SAMPLE_WEIGHT_STRUCT processing")
Thanks,
Kan
Signed-off-by: Thomas Richter <[email protected]>
---
tools/perf/util/evsel.c | 8 +++++---
tools/perf/util/synthetic-events.c | 6 +++++-
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1bf76864c4f2..c9efed5c173d 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2106,10 +2106,12 @@ perf_event__check_size(union perf_event *event,
unsigned int sample_size)
}
void __weak arch_perf_parse_sample_weight(struct perf_sample *data,
- const __u64 *array,
- u64 type __maybe_unused)
+ const __u64 *array, u64 type)
{
- data->weight = *array;
+ if (type & PERF_SAMPLE_WEIGHT)
+ data->weight = *array & 0xffffffff;
+ if (type & PERF_SAMPLE_WEIGHT_STRUCT)
+ data->ins_lat = (*array >> 32) & 0xffff;
}
int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
diff --git a/tools/perf/util/synthetic-events.c
b/tools/perf/util/synthetic-events.c
index b698046ec2db..af7ecbc57cbe 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -1507,9 +1507,13 @@ size_t perf_event__sample_event_size(const struct
perf_sample *sample, u64 type,
}
void __weak arch_perf_synthesize_sample_weight(const struct perf_sample *data,
- __u64 *array, u64 type
__maybe_unused)
+ __u64 *array, u64 type)
{
*array = data->weight;
+ if (type & PERF_SAMPLE_WEIGHT_STRUCT) {
+ *array &= 0xffffffff;
+ *array |= ((u64)data->ins_lat << 32);
+ }
}
int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_format,
